Motor vehicles having four-wheel steering systems are typically defined by a set of front wheels that are steerable in unison with each other and a set of rear wheels that are likewise steerable in unison with each other. The control of the direction and angle of the steering movement of the rear steerable wheels is dependent upon the steering wheel angle and speed of travel of the motor vehicle. When steering the motor vehicle at low speeds, the rear wheels are generally steered out-of-phase or in the opposite direction of the front wheels, thereby enabling the motor vehicle to articulate turns of a small radius. When steering the motor vehicle at high speeds, the rear wheels are generally steered in-phase or in the same direction of the front wheels.
Electronic power steering systems (EPS) and particularly those employing rear wheel steering provide an electronic means of controlling the direction of a vehicle. Such systems provide advantages such as additional flexibility, configurability, and the ability to tailor the system to a particular vehicle. Many steering systems employ electric motors to facilitate positioning the vehicle wheels and positions sensors to measure the actual position of the motor or wheels or both. In such system ensuring proper alignment of the position sensor with a reference or reference motor position is beneficial to reduce or minimize measurement errors. Thus, an automated alignment process presents an opportunity for improving the steering performance of a vehicle and providing simplified and more accurate manufacturing process.
A method of aligning a position sensor in a vehicle with steerable wheels comprising obtaining an absolute position value responsive to a position signal from a handwheel position sensor, obtaining a relative position value responsive to an encoder signal count from a position encoder 50, and obtaining an index position value responsive to an index position signal. The method further includes receiving an alignment enable signal and determining a correction factor responsive to the relative position value and the index position value. The method for aligning a position sensor is responsive to at least one of the absolute position value, the relative position value, and the index position value under conditions determined from the status of the alignment enable signal.
A storage medium encoded with a machine-readable computer program code for aligning a position sensor in a vehicle with steerable wheels. The storage medium includes instructions for causing controller to implement method for aligning a position sensor in a vehicle with steerable wheels as described above.
A computer data signal embodied in a carrier wave for aligning a position sensor in a vehicle with steerable wheels. The computer data signal comprising code configured to cause a controller to implement a method for aligning a position sensor in a vehicle with steerable wheels as described above.
A method for aligning a steerable wheel in a vehicle with electric power steering comprising obtaining an alignment correction corresponding to a computed correction of wheel position relative to the vehicle from an alignment apparatus, receiving an alignment enable signal, where the method of aligning is responsive to the alignment correction under conditions determined from the status of the alignment enable signal.
A storage medium encoded with a machine-readable computer program code for aligning a steerable wheel in a vehicle with electric power steering. The storage medium includes instructions for causing controller to implement method for aligning a steerable wheel in a vehicle with electric power steering s as described above.
A computer data signal embodied in a carrier wave for aligning a steerable wheel in a vehicle with electric power steering. The computer data signal comprising code configured to cause a controller to implement a method for aligning a steerable wheel in a vehicle with electric power steering as described above.